This book constitutes the thoroughly refereed post-proceedings of the Third International Workshop on Environments for Multiagent Systems, E4MAS 2006, held in Hakodate, Japan in May 2006. The 15 revised papers in this volume are organized in topical sections on models, architecture, and design, mediated interaction and stigmery, governing environment, and applications.

Models, Architecture, and Design.- A Reference Architecture for Situated Multiagent Systems.- A Unified Model for Physical and Social Environments.- Exploiting the Environment for Coordinating Agent Intentions.- CArtA gO: A Framework for Prototyping Artifact-Based Environments in MAS.- Mediated Interaction and Stigmery.- Environment as Active Support of Interaction.- Environmental Support for Tag Interactions.- Cognitive Stigmergy: Towards a Framework Based on Agents and Artifacts.- Trace Signals: The Meanings of Stigmergy.- Regulation Function of the Environment in Agent-Based Simulation.- Governing Environment.- Establishing Global Properties of Multi-Agent Systems Via Local Laws.- E4MAS Through Electronic Institutions.- Spatially Distributed Normative Infrastructure.- Enhancing the Environment with a Law-Governed Service for Monitoring and Enforcing Behavior in Open Multi-Agent Systems.- Applications.- Urban Traffic Control with Co-Fields.- Designing Self-organising MAS Environments: The Collective Sort Case.